000 AXNT20 KNHC 120545 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN AUG 12 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE... A VIGOROUS TROPICAL WAVE IS LOCATED OVER THE FAR EASTERN ATLANTIC OCEAN ALONG 20W S OF 20N. A 1006 MB LOW PRES IS NEAR 12N20W OR ABOUT 300 MILES SOUTHEAST OF THE SOUTHERNMOST CAPE VERDE ISLANDS. SHOWERS AND THUNDERSTORMS HAVE CHANGED LITTLE IN ORGANIZATION TONIGHT. HOWEVER...CONDITIONS APPEAR FAVORABLE FOR GRADUAL DEVELOPMENT OF THIS SYSTEM...AND A TROPICAL DEPRESSION COULD FORM DURING THE NEXT DAY OR TWO AS IT MOVES WESTWARD AT 15 TO 20 MPH. MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 50 NM OF 12N23W. ...TROPICAL WAVES... WEAK TROPICAL WAVE IS ALONG 32W SOUTH OF 16N MOVING WEST 10-15 KT. NO DEEP CONVECTIVE PRECIPITATION IS NOTED. WEAK TROPICAL WAVE IS ALONG 48W SOUTH OF 15N MOVING WEST 10-15 KT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN THE ITCZ. HIGH AMPLITUDE TROPICAL WAVE IS ALONG 71W S OF 22N MOVING W 10-15 KT. SCATTERED MODERATE CONVECTION IS NOTED ON THE SOUTHERN END OF THE WAVE AXIS OVER WESTERN VENEZUELA AND NORTHERN COLOMBIA...WHERE THERE IS ALSO A 1008 MB SFC LOW. TROPICAL WAVE IS ALONG 81W SOUTH OF 20N MOVING WEST 10-15 KT. THIS WAVE IS INTERACTING WITH AN UPPER LOW LOCATED OVER THE STRAITS OF FLORIDA NEAR 24N81W. DIFFLUENT BETWEEN THIS UPPER LEVEL LOW AND AN UPPER HIGH OVER THE YUCATAN PENINSULA... COUPLED WITH A BROAD AREA OF LOW PRES OVER THE WESTERN CARIBBEAN SEA AND THIS TROPICAL WAVE ARE PRODUCING DISORGANIZED SHOWERS AND THUNDERSTORMS NEAR JAMAICA...THE CAYMAN ISLANDS...AND CUBA. DEVELOPMENT OF THIS SYSTEM...IF ANY...IS EXPECTED TO BE SLOW TO OCCUR AT IT MOVES WESTWARD INTO THE YUCATAN PENINSULA AT ABOUT 10 MPH. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 14N17W 10N25W 10N40W 9N60W. BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION... SCATTERED MODERATE CONVECTION IS FROM 7N-11N BETWEEN 35W-47W. DISCUSSION... THE GULF OF MEXICO... THE COMBINATION OF A STRONG UPPER HIGH OVER TEXAS-LOUISIANA AND AND AN UPPER LOW CURRENTLY OVER NORTH-CENTRAL MEXICO CONTINUES TO PRODUCE STRONG UPPER E TO NE WIND FLOW ACROSS THE NORTHERN GULF WATERS. ANOTHER UPPER LOW IS SPINNING JUST EAST OF THE FLORIDA KEY OVER THE STRAITS OF FLORIDA AND IS FORECAST TO MOVE WEST OVERNIGHT INCREASING THE CHANGE OF SHOWERS OVER SOUTH FLORIDA AND THE KEYS. MOSAIC DOPPLER RADAR FROM THE SE U.S. SHOWS AND AREA OF SHOWERS WITH EMBEDDED TSTMS NEAR THE WEST COAST OF FLORIDA JUST N OF THE FLORIDA KEYS. THE SFC PATTERN REMAINS WEAK WITH A 1014 MB HIGH CENTER S OF LOUISIANA NEAR 27N90W. THIS WEAK PRES GRAD IS ALLOWING WINDS TO REMAIN LIGHT ACROSS THE ENTIRE REGION. A SFC TROUGH OVER THE SE U.S. IS GENERATING SOME SHOWER ACTIVITY OVER THE FLORIDA PANHANDLE AND THE NE CORNER OF THE GULF. THE CARIBBEAN SEA... A VERY MOIST AND UNSTABLE AIRMASS REMAINS OVER THE WESTERN HALF OF THE CARIBBEAN SEA THANKS TO A PAIR OF TROPICAL WAVES...A BROAD AREA OF LOW PRES AND TWO UPPER LEVEL FEATURES. THEY ARE...AN UPPER LOW SPINNING OVER THE STRAITS OF FLORIDA NEAR 24N81W AND AN UPPER HIGH OVER THE YUCATAN PENINSULA. DIFFLUENCE BETWEEN THESE TWO SYSTEM IS ENHANCING THE CONVECTIVE ACTIVITY OVER JAMAICA...THE CAYMAN ISLANDS...CUBA AND NORTHERN CENTRAL AMERICA...MAINLY OVER PARTS OF NICARAGUA AND HONDURAS. A TUTT LOW IS OVER THE NORTHERN LEEWARD ISLANDS BRINGING UPPER DRY AIR AND SUBSIDENCE TO THE NE CARIBBEAN...INCLUDING PUERTO RICO AND THE UK/US VIRGIN ISLANDS. THIS LOW WILL MOVE WESTWARD OVER PUERTO RICO AND HISPANIOLA MONDAY THROUGH TUE. LIGHT TO MODERATE WINDS ARE FOUND IN THE WRN PORTION OF THE BASIN AND MODERATE TO FRESH WINDS IN THE E AND CENTRAL CARIB. THE FRESH TRADES WILL PERSIST OVER THE CENTRAL CARIBBEAN THROUGH MON. THE ATLANTIC OCEAN... THE AFOREMENTIONED UPPER LOW LOCATED OVER THE STRAITS OF FLORIDA IS ALSO SUPPORTING SOME SHOWER ACTIVITY ACROSS THE BAHAMAS. AN UPPER LOW IS OVER THE NORTHERN LEEWARD ISLANDS WITH A TROUGH EXTENDING NE ACROSS THE CENTRAL ATLC. THE REMAINDER OF THE FORECAST AREA IS DOMINATING BY AN UPPER HIGH LOCATED NEAR 22N25W. WV IMAGERY SHOWS ABUNDANT DRY AIR/SUBSIDENCE ALOFT N OF 20N AND E OF 50W...ALLOWING FAIR WEATHER TO PREVAIL. AT THE SFC...THE MAIN WEATHER FEATURE IS THE AZORES HIGH WITH A 1025 MB CENTER NEAR 36N32W. AS IS USUAL FOR THIS TIME OF THE YEAR...THIS HIGH EXTENDS A RIDGE SW REACHING THE NE CARIBBEAN AND THE BAHAMAS. PATCHES OF LOW/MID CLOUDS AND MODERATE TRADE WINDS ARE FOUND UNDER THE INFLUENCE OF THIS SYSTEM. $$ GR